The present invention relates to improvements in a structure for mounting a sound absorbing member on the top portion of a sound insulation wall for preventing noise and the like caused by running vehicles on an expressway or the like and a method of mounting the sound absorbing member.
As sound absorbing apparatuses which are capable of preventing noise caused from an expressway, a railway, a plant or the like and absorbing and eliminating diffracted noise and which is mounted on the top end of a sound insulation wall, a structure disclosed in Japanese Patent Unexamined Publication No. Hei. 6-235209 has been known. A structure for mounting the sound absorbing member which is the main component of the sound absorbing unit of the foregoing type requires various operations including operations for screwing bolts and nuts which are performed on the inner and outer portions of the sound insulation wall.
Therefore, when the operations are performed for an elevated expressway, the operations on the road side, that is, on positions at a sound source side are required. Moreover, mounting operations which are performed in the portion opposite to the road, that is, on the outside of the sound insulation wall opposite to the sound source side must be performed. Therefore, a scaffolding or the like must be built on the outside of the sound insulation wall, or a heavy machine, such as an overhang car, must be used. The safety of the operations cannot always be secured. Moreover, various elements including the sound absorbing members must be prepared to be adaptable to the specified dimensions of the elements for the sound insulation wall. As a result, a large number of elements and working processes are required, thus causing a problem to arise in that an excessively long time and great labor are required for repair and maintenance.